Transmission power control method, tpc command transmission method, and radio communication device

ABSTRACT

In a radio communication system where A-DPCH (Associated-Dedicated Physical Channel) to which soft hand-over is applied and HS-DPCCH (High Speed-Dedicated Physical Control Channel) to which hard hand-over is applied are mixed, in order to perform appropriate transmission power control of the HS-DPCCH, an HO judging section  11  judges whether the A-DPCH is in a soft hand-over state, and a transmission radio section  23 , when the A-DPCH is not in the soft hand-over state, performs transmission power control of the HS-DPCCH according to a TPC command for the A-DPCH transmitted on the A-DPCH, and when the A-DPCH is in the soft hand-over state, performs transmission power control of the HS-DPCCH according to a TPC command for the HS-DPCCH transmitted on the HS-DPCCH.

TECHNICAL FIELD

The present invention relates to a transmission power control method, aTPC command transmitting method, and a radio communication apparatus.

BACKGROUND ART

In the field of radio communication systems, HSDPA (High Speed DownlinkPacket Access) has been proposed wherein a plurality of communicationterminals share a downlink channel of high speed and large capacity andhigh speed packet transmission is performed on the downlink. Moreover,these days technology for increasing packet transmission speed on anuplink (hereinafter, this technology being called Fast-UL (Fast-Uplink))has been under study. In the HSDPA, a plurality of channels are usedsuch as an HS-PDSCH (High Speed-Physical Downlink Shared Channel), anA-DPCH (Associated-Dedicated Physical Channel), and an HS-DPCCH (HighSpeed-Dedicated Physical Control Channel). It is envisioned that also inthe Fast-UL, a plurality of channels will be used such as an HS-PUSCH(High Speed-Physical Uplink Shared Channel), the A-DPCH, and theHS-DPCCH.

The HS-PDSCH is a downlink shared channel used in transmission ofpackets. The HS-PUSCH is an uplink shared channel used in transmissionof packets. The A-DPCH is an uplink or downlink dedicated associatedchannel associating a shared channel, and has a pilot signal, TPC(Transmission Power Control) commands, control signals for maintainingcommunication, and the like transmitted thereon. The HS-DPCCH is anuplink or downlink dedicated control channel, and has signals forcontrolling a shared channel such as an ACK/NACK signal and a CQI(Channel Quality Indicator) signal transmitted thereon. Note that theACK signal is a signal indicating that a high speed packet transmittedfrom a base station or a communication terminal was correctlydemodulated in a communication terminal or a base station, and that theNACK signal is a signal indicating that a high speed packet transmittedfrom a base station or a communication terminal could not be correctlydemodulated in a communication terminal or a base station. Furthermore,the CQI is a signal generated based on the channel quality andindicating the combination of, for example, the modulation scheme, blocksize, transmission power adjustment value, and the like of a packet. Inthe HSDPA, using the CQI, communication terminals notify theircommunication partner of the modulation scheme, block size, transmissionpower adjustment value, and the like that they desire. The CQI in theFast-UL is also a signal generated based on the channel quality, but itsspecific contents have not yet been decided.

Note that in the Fast-UL, both uplink and downlink channels exist foreach of the A-DPCH and HS-DPCCH. On the uplink HS-DPCCH, the CQI istransmitted. On the downlink HS-DPCCH, the ACK/NACK signal istransmitted. On the other hand, in the HSDPA, both uplink and downlinkchannels exist for the A-DPCH, while only an uplink channel exists forthe HS-DPCCH. On the uplink HS-DPCCH, the CQI and the ACK/NACK signalare transmitted. Moreover, soft hand-over (SHO) is applied to theA-DPCH. On the other hand, hard hand-over (HHO) is applied to theHS-PDSCH, HS-PUSCH, and HS-DPCCH, so that the HS-PDSCH, HS-PUSCH, andHS-DPCCH are always connected to only one base station. Moreover, thetiming for executing HHO on HS-PDSCH or HS-PUSCH is the same as the HHOtiming of HS-DPCCH.

Transmission power control of the HS-DPCCH will be explained belowtaking the Fast-UL as an example using FIGS. 1 to 3. FIG. 1 shows thecase where the A-DPCH is not in a SHO state, and FIGS. 2 and 3 show thecase where the A-DPCH is in the SHO state. Here, the A-DPCH being not inthe SHO state refers to the case where a communication terminal has theA-DPCH connected to only one base station, and the A-DPCH being in theSHO state refers to the case where a communication terminal has theA-DPCHs connected to a plurality of base stations at the same time.

As shown in FIG. 1, the transmission power of the A-DPCH is controlledby generally well-known closed-loop transmission power control accordingto the TPC command such that a reception SIR of the A-DPCH is kept at atarget SIR. Meanwhile, for the HS-DPCCH, the same transmission powercontrol as for the A-DPCH is performed according to the TPC command forthe A-DPCH. By this means, when the A-DPCH is not in the SHO state, thereception SIR of the HS-DPCCH can meet an SIR requirement.

When the communication terminal moves from a base station 1 towards abase station 2, the communication terminal connects the A-DPCHs to boththe base stations 1 and 2, so that the A-DPCH gets in the SHO state.When the A-DPCH is in the SHO state, the transmission power control ofthe HS-DPCCH to which the HHO is applied is performed as follows.

First, transmission power control of the uplink HS-DPCCH will beexplained using FIG. 2. When the A-DPCH gets in the SHO state, both thebase stations 1 and 2 receive the A-DPCH signal transmitted from thecommunication terminal. The base station 1 generates such a TPC commandthat the reception SIR at the base station 1 approaches a target SIR andtransmits the TPC command to the communication terminal. Also, the basestation 2 generates such a TPC command that the reception SIR at thebase station 2 approaches a target SIR and transmits the TPC command tothe communication terminal. If all of a plurality of received TPCcommands are a TPC command to increase the transmission power, thecommunication terminal increases the transmission power of the A-DPCH,and if at least one of the plurality of received TPC commands is a TPCcommand to decrease the transmission power, the communication terminaldecreases the transmission power of the A-DPCH. Hence, when the basestation 1 has transmitted a TPC command to increase the transmissionpower and the base station 2 has transmitted a TPC command to decreasethe transmission power, the communication terminal decreases thetransmission power of the A-DPCH signal. Because the transmission powerof the HS-DPCCH is controlled in the same way as that of the A-DPCH, thetransmission power of the HS-DPCCH is also decreased along with that ofthe A-DPCH as shown in FIG. 2.

Here, for the uplink A-DPCH, when the A-DPCH is in the SHO state, theA-DPCH signal received by the base station 1 and the A-DPCH signalreceived by the base station 2 are selectively combined at a controlstation. Therefore, even if the transmission power of the A-DPCH isdecreased as above, the SIR of the uplink A-DPCH at the control stationmeets an SIR requirement without causing a problem.

On the other hand, the HS-DPCCH to which the HHO is applied is connectedto only one of the base stations even when the A-DPCH is in the SHOstate. Thus, if the transmission power of the uplink HS-DPCCH isdecreased along with the transmission power of the uplink A-DPCH asabove, the SIR of the uplink HS-DPCCH may not meet an SIR requirement.In order to prevent this, the transmission power of the HS-DPCCH may beset at the sum of the transmission power of the A-DPCH and an offset.

Next, transmission power control of the downlink HS-DPCCH will beexplained using FIG. 3. When the A-DPCH gets in the SHO state, thecommunication terminal receives the A-DPCH signals transmitted from boththe base stations 1 and 2. The communication terminal combines theA-DPCH signals transmitted from the base stations 1 and 2 and generatessuch a TPC command that the reception SIR of the combined signalapproaches a target SIR and transmits the same TPC command to both thebase stations 1 and 2.

Here, even when the reception SIR is less than the target SIR with theA-DPCH signal transmitted from the base station 1 only, thecommunication terminal transmits a TPC command to decrease thetransmission power as shown in FIG. 3 if the reception SIR of thecombined signal is greater than the target SIR. Because the transmissionpower of the HS-DPCCH is controlled in the same way as that of theA-DPCH, as illustrated in FIG. 3, at the base station 1, thetransmission power of the HS-DPCCH signal is also lowered in accordancewith the lowering of the transmission power of the A-DPCH signal as perthe TPC command.

The HS-DPCCH to which the HHO is applied is connected to only one of thebase stations even when the A-DPCH is in the SHO state. Therefore, ifthe transmission power of the downlink HS-DPCCH is decreased along withthe transmission power of the downlink A-DPCH being decreased as above,at the communication terminal the SIR of the downlink HS-DPCCH may notmeet an SIR requirement. In order to prevent this, the transmissionpower of the HS-DPCCH may be set at the sum of the transmission power ofthe A-DPCH and an offset.

However, if the transmission power of the HS-DPCCH is set at the sum ofthe transmission power of the A-DPCH and an offset as mentioned above,when the A-DPCH is not in the SHO state, or when enough SIR is obtainedin communication with only one base station while the A-DPCH is in theSHO state, the transmission power of the HS-DPCCH will be excessive. Ifthe transmission power of the HS-DPCCH is excessive, the transmissionpower, a limited radio resource, is consumed excessively. Thus, not onlysystem throughput is reduced, but also interferences of the HS-DPCCH inother channels become large, thereby reducing system capacity. Note thatthis problem occurs not only with the Fast-UL but also with the HSDPA.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a transmission powercontrol method, TPC command transmitting method, and radio communicationapparatus that, in a radio communication system operating in a mixedchannel environment involving a SHO-applicable A-DPCH and aHHO-applicable HS-DPCCH, performs appropriate transmission power controlof the HS-DPCCH so that the transmission power of the HS-DPCCH do notbecome excessive and the reception SIR of the HS-DPCCH can be maintainedat a required SIR.

In order to solve the previously mentioned problem and achieve theobject, according to the present invention, in a radio communicationsystem where A-DPCH to which SHO is applied and HS-DPCCH to which HHO isapplied are mixed, when the A-DPCH is not in a SHO state, transmissionpower control of an HS-DPCCH is performed according to an A-DPCH TPCcommand transmitted on A-DPCH, and when the A-DPCH is in the SHO state,transmission power control of the HS-DPCCH is performed according to aHS-DPCCH TPC command transmitted on HS-DPCCH.

According to this feature, in a radio communication system where A-DPCHto which SHO is applied and HS-DPCCH to which HHO is applied are mixed,appropriate transmission power control of the HS-DPCCH can be performedeven when the A-DPCH is in the SHO state.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for explaining conventional transmission power controlwhen A-DPCH is not in a SHO state;

FIG. 2 is a view for explaining conventional transmission power controlof an uplink HS-DPCCH;

FIG. 3 is a view for explaining conventional transmission power controlof a downlink HS-DPCCH;

FIG. 4 is a block diagram showing the configuration of a radiocommunication apparatus according to one embodiment of the presentinvention;

FIG. 5 is a view for explaining transmission power control of an uplinkHS-DPCCH according to the embodiment of the present invention;

FIG. 6 is a view for explaining transmission power control of a downlinkHS-DPCCH according to the embodiment of the present invention;

FIG. 7 is a view for explaining a relationship between transmissionpowers of base stations and reception SIRs of a communication terminalaccording to the embodiment of the present invention; and

FIG. 8 is a view for explaining the start and end timings fortransmitting TPC commands for the HS-DPCCH according to the embodimentof the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below. FIG. 4is a block diagram showing the configuration of a radio communicationapparatus according to one embodiment of the present invention. Thisradio communication apparatus is provided in a communication terminalapparatus and a base station apparatus in a mobile communication system.Moreover, this radio communication apparatus is used in a mobilecommunication system where the Fast-UL and/or HSDPA are implemented.

An HO (hand-over) judging section 11 judges whether the A-DPCH is in theSHO state, and inputs the judging result into TPC command extractingsection 17, SIR measurement section 18, TPC command generating section19, and transmission radio section 23. Note that the method of judgingwhether the A-DPCH is in the SHO state is described later.

A receiving section 100 comprises reception radio section 13,despreading section 14, demodulator 15, and decoder 16.

The reception radio section 13 performs processes such asdown-conversion, AGC (Automatic Gain Control), and A/D conversion on asignal received via an antenna 12. The despreading section 14 despreadsthe received signal with a spreading code assigned to each channel. Thedemodulator 15 demodulates the despread signal such as a QPSK modulatedsignal. The demodulated signal is input into the decoder 16 and an SIRmeasurement section 18. The decoder 16 performs error correctiondecoding and CRC (Cyclic Redundancy Check) on the demodulated receivedsignal to decode the demodulated received signal. By this means,reception data (a bit sequence) is obtained. The reception data is inputinto the TPC command extracting section 17.

The TPC command extracting section 17 extracts a TPC command included ina timeslot of the reception data based on the judging result of the HOjudging section 11. When the HO judging section 11 has judged that theA-DPCH is not in the SHO state, the TPC command extracting section 17extracts a TPC command for the A-DPCH from the reception data on theA-DPCH. In contrast, when the HO judging section 11 has judged that theA-DPCH is in the SHO state, the TPC command extracting section 17extracts a TPC command for the HS-DPCCH from the reception data on theHS-DPCCH in addition to the above-described operation performed when theA-DPCH is not in the SHO state. The extracted TPC commands are inputinto the transmission radio section 23.

The SIR measurement section 18 measures the SIR of symbols of a pilotsequence out of the received signal based on the judging result of theHO judging section 11. When the HO judging section 11 has judged thatthe A-DPCH is not in the SHO state, the SIR measurement section 18measures the SIR of the received signal on the A-DPCH. In contrast, whenthe HO judging section 11 has judged that the A-DPCH is in the SHOstate, the SIR measurement section 18 measures the SIR of the receivedsignal on the HS-DPCCH in addition to the above-described operationperformed when the A-DPCH is not in the SHO state. The measured SIRs areinput into the TPC command generating section 19.

The TPC command generating section 19 generates a TPC command based onthe judging result of the HO judging section 11. When the HO judgingsection 11 has judged that the A-DPCH is not in the SHO state, the TPCcommand generating section 19 compares the SIR of the A-DPCH with atarget SIR and, based on the comparing result, generates a TPC commandfor the A-DPCH. In contrast, when the HO judging section 11 has judgedthat the A-DPCH is in the SHO state, the TPC command generating section19 compares the SIR of the HS-DPCCH with a target SIR and, based on thecomparing result, generates a TPC command for the HS-DPCCH in additionto the above-described operation performed when the A-DPCH is not in theSHO state. Note that when the measured SIR is at or above the targetSIR, a TPC command to decrease the transmission power (Down) isgenerated and when the measured SIR is below the target SIR, a TPCcommand to increase the transmission power (Up) is generated. Thegenerated TPC commands are input into an encoder 20.

A transmitting section 200 comprises encoder 20, modulator 21, spreadingsection 22, and transmission radio section 23.

The encoder 20 performs convolution encoding and CRC encoding ontransmit data (a bit sequence) to encode the transmit data and form atransmit frame having a plurality of timeslots. At this time, a TPCcommand for the A-DPCH is embedded in a timeslot of the A-DPCH. Inaddition, when a TPC command for the HS-DPCCH is input from the TPCcommand generating section 19, the TPC command for the HS-DPCCH isembedded in a timeslot of the HS-DPCCH.

The modulator 21 performs modulation such as QPSK on the transmit data.The spreading section 22 spreads the modulated transmit signal with aspreading code assigned to each channel.

After performing processes such as D/A conversion, transmission powercontrol, and up-conversion on the spread transmit signal, thetransmission radio section 23 transmits the transmit signal via theantenna 12. Here, the transmission radio section 23 performs thetransmission power control based on the judging result of the HO judgingsection 11.

When the HO judging section 11 has judged that the A-DPCH is not in theSHO state, the transmission radio section 23 controls the transmissionpower of the A-DPCH according to the TPC command for the A-DPCH andalong therewith, controls the transmission power of the HS-DPCCH at thesame power as that of the A-DPCH or the sum of the transmission power ofthe A-DPCH and an offset. That is, when the A-DPCH is not in the SHOstate, the transmission power of the HS-DPCCH is also controlledaccording to the TPC command for the A-DPCH. Hence, when the A-DPCH isnot in the SHO state, the change in the transmission power of theHS-DPCCH follows the change in that of the A-DPCH.

On the other hand, when the HO judging section 11 has judged that theA-DPCH is in the SHO state, the transmission radio section 23 controlsthe transmission power of the A-DPCH according to the TPC command forthe A-DPCH and along therewith, controls the transmission power of theHS-DPCCH according to the TPC command for the HS-DPCCH. That is, thetransmission powers of the A-DPCH and HS-DPCCH are controlledindependently of each other according to the respective different TPCcommands. Hence, when the A-DPCH is in the SHO state, the change in thetransmission power of the HS-DPCCH is different from the change in thatof the A-DPCH.

Note that in the case of the radio communication apparatus having theabove configuration provided in a base station, processing for allcommunication terminal apparatuses with which the base stationcommunicates is performed in parallel.

Next, taking the Fast-UL as an example, transmission power control ofthe HS-DPCCH will be explained. Note that transmission power control ofthe A-DPCH is the same as in the prior art, hence a description thereofbeing omitted.

When the A-DPCH is not in the SHO state, the transmission power of theHS-DPCCH is controlled at the same power as that of the A-DPCH or thesum of the transmission power of the A-DPCH and an offset. That is, whenthe A-DPCH is not in the SHO state, the transmission power of theHS-DPCCH is controlled according to the A-DPCH TPC command transmittedon the A-DPCH. Thus, when the A-DPCH is not in the SHO state, thereception SIR of the HS-DPCCH can meet an SIR requirement.

On the other hand, when the A-DPCH is in the SHO state, the transmissionpower control of the HS-DPCCH, to which the HHO is applied, is performedindependently of that for the A-DPCH. That is, when the A-DPCH is in theSHO state, the transmission power of the HS-DPCCH is controlledaccording to the HS-DPCCH TPC command transmitted on the HS-DPCCH. FIGS.5 and 6 show the case of the A-DPCH being in the SHO state.

First, transmission power control of the uplink HS-DPCCH will beexplained using FIG. 5. When the A-DPCH gets in the SHO state, the basestation 1 starts transmitting the TPC command for the HS-DPCCH to thecommunication terminal on the downlink HS-DPCCH. According to the TPCcommand, the communication terminal controls the transmission power ofthe uplink HS-DPCCH.

For example, when for the A-DPCH, the base station 1 transmits a TPCcommand to increase the transmission power and the base station 2transmits a TPC command to decrease the transmission power as shown inFIG. 5, the communication terminal decreases the transmission power ofthe A-DPCH signal. When the A-DPCH is in the SHO state, the base station1 transmits a TPC command for the A-DPCH and a TPC command for theHS-DPCCH independent thereof to the communication terminal. Therefore,even when decreasing the transmission power of the uplink A-DPCH signal,the communication terminal increases the transmission power of theuplink HS-DPCCH irrelevantly of that of the A-DPCH, if the base station1 has transmitted a TPC command to increase the transmission power ofthe HS-DPCCH. By this means, even when the A-DPCH is in the SHO state,the transmission power of the HS-DPCCH is appropriately controlled, sothat at the base station to which the HS-DPCCH is connected, thereception SIR of the HS-DPCCH can be maintained at a required SIR.

Next, transmission power control of the downlink HS-DPCCH will beexplained using FIG. 6. When the A-DPCH gets in the SHO state, thecommunication terminal starts transmitting TPC commands for the HS-DPCCHto the base station 1 on the uplink HS-DPCCH. According to the TPCcommands, the base station 1 controls the transmission power of thedownlink HS-DPCCH.

For example, when for the A-DPCH, the communication terminal combinesthe A-DPCH signal transmitted from the base station 1 and the A-DPCHsignal transmitted from the base station 2 as shown in FIG. 6, andgenerates such a TPC command that the reception SIR of the combinedsignal is kept at a target SIR, and then transmits the same TPC commandto both the base stations 1 and 2. In the example of FIG. 6, a TPCcommand to decrease the transmission power is being sent to both basestations. According to the TPC command, the base stations 1 and 2decrease the transmission power of the downlink A-DPCH. When the A-DPCHis in the SHO state, the communication terminal transmits a TPC commandfor the A-DPCH and a TPC command for the HS-DPCCH independent thereof tothe base station 1. Therefore, even when decreasing the transmissionpower of the downlink A-DPCH signal, the base station 1 increases thetransmission power of the downlink HS-DPCCH irrelevantly of that of theA-DPCH, if the communication terminal has transmitted a TPC command toincrease the transmission power of the HS-DPCCH. By this means, evenwhen the A-DPCH is in the SHO state, the transmission power of theHS-DPCCH is appropriately controlled, so that at the communicationterminal the reception SIR of the HS-DPCCH can be maintained at arequired SIR.

Next, taking the downlink as an example, a relationship between thetransmission powers of the base stations and the reception SIRs of thecommunication terminal will be explained using FIG. 7.

The communication terminal always receives a CPICH (Common PilotChannel) signal (CPICH1) being transmitted at a constant power from thebase station 1 and a CPICH signal (CPICH2) being transmitted at aconstant power from the base station 2.

Before the SHO of the A-DPCH starts, that is, when the A-DPCH isconnected to only the base station 1, if the communication terminalmoves away from the base station 1 towards the base station 2, thetransmission power 320 of the A-DPCH at the base station 1 increases inorder to maintain the reception SIR 360 of the A-DPCH at thecommunication terminal to be constant. Along therewith, the transmissionpower 310 of the HS-DPCCH at the base station 1 increases. Hence, thereception SIR 350 of the HS-DPCCH at the communication terminal is alsomaintained constant.

With the communication terminal moving further towards the base station2, when the difference between the reception SIRs of the CPICH1 and theCPICH2 at the communication terminal reaches, e.g., 3 dB, the A-DPCHgets in the SHO state. Thus, by monitoring the difference between thereception SIRs of the CPICH1 and the CPICH2, the communication terminaldetects the start and end of the SHO, so that it can be judged whetherthe A-DPCH is in the SHO state. Note that the base station can judgewhether the A-DPCH is in the SHO state also via a control signal sentfrom an upper layer, that is, a notice from a control station. Likewise,the communication terminal also can judge whether the A-DPCH is in theSHO state via a notice from a control station.

When the A-DPCH gets in the SHO state, the A-DPCH is connected to thebase station 2 as well. Thus, as the transmission power 340 of theA-DPCH at the base station 2 increases, the transmission power 320 ofthe A-DPCH at the base station 1 decreases. During this time, thecommunication terminal combines the A-DPCH signals from the basestations 1 and 2, and thus the reception SIR 360 of the A-DPCH ismaintained constant. Meanwhile, the transmission power of the HS-DPCCHis controlled according to TPC commands for the HS-DPCCH independentlyof the A-DPCH when the A-DPCH is in the SHO state. Therefore, when theA-DPCH is in the SHO state, even if the transmission power 320 of theA-DPCH at the base station 1 decreases, the transmission power 310 ofthe HS-DPCCH at the base station 1 increases. Thus, the reception SIR350 of the HS-DPCCH at the communication terminal is maintained constanteven when the A-DPCH is in the SHO state.

With the communication terminal moving further towards the base station2, when the reception SIR of the CPICH1 becomes, e.g., 3 dB lower thanthat of the CPICH2, the HS-DPCCH is handed over to the base station 2 inthe HHO manner. After the HS-DPCCH has been HHO-handed over, the TPCcommand for the HS-DPCCH is transmitted from the base station 2 insteadof the base station 1. Because, after the HS-DPCCH has undergone HHO,the A-DPCH is still in the SHO state, the transmission power of theHS-DPCCH is controlled according to TPC commands for the HS-DPCCHindependently of the A-DPCH. Then, as the communication terminal movesyet further towards the base station 2, the transmission power 330 ofthe HS-DPCCH at the base station 2 gradually decreases.

With the communication terminal moving still further towards the basestation 2, when at the communication terminal the reception SIR of theCPICH1 goes down at, e.g., 5 dB lower than that of the CPICH2, the SHOof the A-DPCH ends. That is, the A-DPCH is put in a state of beingconnected to only the base station 2. After the SHO of the A-DPCH ends,the transmission power of the HS-DPCCH is controlled according to theTPC command for the A-DPCH. Therefore, when the communication terminalmoves yet further towards the base station 2, as the transmission power340 of the A-DPCH at the base station 2 decreases in order to maintainthe reception SIR 360 of the A-DPCH at the communication terminalconstant, the transmission power 330 of the HS-DPCCH at the base station2 also decreases. Thus, the reception SIR 350 of the HS-DPCCH at thecommunication terminal is also maintained constant.

Next, the start timing and end timing for transmitting TPC commands forthe HS-DPCCH will be explained using FIG. 8.

For the downlink A-DPCH, whether or not the A-DPCH is in the SHO state,a TPC command to be used in transmission power control of the uplinkA-DPCH and a pilot to be used in the measurement of SIR of the downlinkA-DPCH are transmitted in each timeslot from a base station to thecommunication terminal. Likewise, for the uplink A-DPCH, whether or notthe A-DPCH is in the SHO state, a TPC command to be used in transmissionpower control of the downlink A-DPCH and a pilot to be used in themeasurement of SIR of the uplink A-DPCH are transmitted in each timeslotfrom the communication terminal to the base station.

Meanwhile, for the downlink HS-DPCCH, only when the A-DPCH is in the SHOstate, a TPC command to be used in transmission power control of theuplink HS-DPCCH and a pilot to be used in the measurement of SIR of thedownlink HS-DPCCH are transmitted in each timeslot from a base stationto the communication terminal. Likewise, for the uplink HS-DPCCH, onlywhen the A-DPCH is in the SHO state, a TPC command to be used intransmission power control of the downlink HS-DPCCH and a pilot to beused in the measurement of SIR of the uplink HS-DPCCH are transmitted ineach timeslot from the communication terminal to the base station. Thatis, the transmission of TPC command for the HS-DPCCH starts when the SHOof the A-DPCH starts, and the transmission of TPC command for theHS-DPCCH ends when the SHO of the A-DPCH ends.

Note that although data, pilots, and TPC commands are time-multiplexedin FIG. 8, they may be IQ-multiplexed.

As described above, the synchronization between the SHO start/endtimings for the A-DPCH and the transmission start/end timings of sendingTPC commands for the HS-DPCCH makes it unnecessary to transmit TPCcommands for the HS-DPCCH when the A-DPCH is not in the SHO state, whichhelps to reduce interferences due to the HS-DPCCH affecting otherchannels.

Furthermore, battery consumption of the communication terminal can besuppressed. Moreover, when the A-DPCH is in the SHO state, a TPC commandfor the HS-DPCCH is transmitted in each timeslot on the HS-DPCCH. Hence,the transmission power control of the HS-DPCCH can be accuratelyperformed even when the communication terminal moves at high speed.

While, in the present embodiment, the description has been made takingthe Fast-UL as an example, not being limited to this, the presentinvention can be applied to all radio communication systems wherededicated channels to which soft hand-over is applied and dedicatedchannels to which hard hand-over is applied are mixed and where thededicated channels to which hard hand-over is applied are uplink anddownlink channels.

As described above, according to the present invention, the appropriatetransmission power control is performed on the HS-DPCCH, so that thetransmission power of the HS-DPCCH does not become excessive and thereception SIR of the HS-DPCCH can be maintained at a required SIR.

The present description is based on Japanese Patent Application No.2002-239734 filed on Aug. 20, 2002, which is herein incorporated byreference.

Industrial Applicability

The present invention can be applied to radio communication terminalapparatuses and radio communication base station apparatuses used in amobile communication system.

FIG. 1

-   BASE STATION 1-   TPC COMMAND-   COMMUNICATION TERMINAL    FIG. 4-   11: HO JUDGING SECTION-   13: RECEPTION RADIO SECTION-   14: DESPREADING SECTION-   15: DEMODULATOR-   16: DECODER-   17: TPC COMMAND EXTRACTING SECTION-   18: SIR MEASUREMENT SECTION-   19: TPC COMMAND GENERATING SECTION-   20: ENCODER-   21: MODULATOR-   22: SPREADING SECTION-   23: TRANSMISSION RADIO SECTION-   TRANSMISSION DATA-   RECEPTION DATA    FIG. 7-   CONNECTED TO BASE STATION 1-   SHO START-   SHO STATE-   TIMING WHEN HS-DPCCH UNDERGOES HHO-   SHO END-   CONNECTED TO BASE STATION 2-   TRANSMISSION POWER OF BASE STATION 1-   TRANSMISSION POWER OF BASE STATION 2-   RECEPTION SIRs OF COMMUNICATION TERMINAL-   TIME    FIG. 8-   SHO START-   SHO STATE-   SHO END-   TRANSMISSION FROM BASE STATION-   (DOWNLINK)-   1 TIMESLOT-   TRANSMISSION FROM COMMUNICATION TERMINAL-   (UPLINK)-   DATA PORTION-   PILOT-   TPC COMMAND

1. A transmission power control method used in a radio communicationsystem where a first dedicated channel to which soft hand-over isapplied and a second dedicated channel to which hard hand-over isapplied are mixed, wherein when the first dedicated channel is not in asoft hand-over state, transmission power control of the second dedicatedchannel is performed according to a TPC command for the first dedicatedchannel transmitted on the first dedicated channel, and when the firstdedicated channel is in the soft hand-over state, transmission powercontrol of the second dedicated channel is performed according to a TPCcommand for the second dedicated channel transmitted on the seconddedicated channel.
 2. A TPC command transmitting method used in a radiocommunication system where a first dedicated channel to which softhand-over is applied and a second dedicated channel to which hardhand-over is applied are mixed, wherein when the first dedicated channelis in a soft hand-over state, a TPC command for the first dedicatedchannel is transmitted on the first dedicated channel and a TPC commandfor the second dedicated channel is transmitted on the second dedicatedchannel.
 3. A TPC command transmitting method used in a radiocommunication system where a first dedicated channel to which softhand-over is applied and a second dedicated channel to which hardhand-over is applied are mixed, wherein after soft hand-over of thefirst dedicated channel starts, transmission of a TPC command for thesecond dedicated channel starts on the second dedicated channel.
 4. Aradio communication apparatus used in a radio communication system wherea first dedicated channel to which soft hand-over is applied and asecond dedicated channel to which hard hand-over is applied are mixed,said radio communication apparatus comprising: a judging section thatjudges whether the first dedicated channel is in a soft hand-over state;an extracting section that, when said judging section judges that thefirst dedicated channel is not in the soft hand-over state, extractsonly a TPC command for the first dedicated channel from a receivedsignal, and when said judging section judges that the first dedicatedchannel is in the soft hand-over state, extracts both a TPC command forthe first dedicated channel and a TPC command for the second dedicatedchannel from the received signal; and a control section that, when saidjudging section judges that the first dedicated channel is not in thesoft hand-over state, performs both transmission power control of thefirst dedicated channel and transmission power control of the seconddedicated channel according to the TPC command for the first dedicatedchannel extracted by said extracting section, and when said judgingsection judges that the first dedicated channel is in the soft hand-overstate, performs transmission power control of the first dedicatedchannel according to the TPC command for the first dedicated channelextracted by said extracting section, and performs transmission powercontrol of the second dedicated channel according to the TPC command forthe second dedicated channel extracted by said extracting section.
 5. Aradio communication apparatus used in a radio communication system wherea first dedicated channel to which soft hand-over is applied and asecond dedicated channel to which hard hand-over is applied are mixed,said radio communication apparatus comprising: a judging section thatjudges whether the first dedicated channel is in a soft hand-over state;a measuring section that, when said judging section judges that thefirst dedicated channel is not in the soft hand-over state, measuresonly an SIR of the first dedicated channel and, when said judgingsection judges that the first dedicated channel is in the soft hand-overstate, measures both the SIR of the first dedicated channel and an SIRof the second dedicated channel; a generating section that, when saidjudging section judges that the first dedicated channel is not in thesoft hand-over state, generates only a TPC command for the firstdedicated channel based on a result of comparing the SIR of the firstdedicated channel measured by said measuring section with a target SIR,and when said judging section judges that the first dedicated channel isin the soft hand-over state, generates a TPC command for the firstdedicated channel based on a result of comparing the SIR of the firstdedicated channel measured by said measuring section with a target SIR,and a TPC command for the second dedicated channel based on a result ofcomparing the SIR of the second dedicated channel measured by saidmeasuring section with a target SIR; and a transmitting section thattransmits one or both of the TPC command for the first dedicated channeland the TPC command for the second dedicated channel generated by saidgenerating section.